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Unit #3: Instructions for Life” Study Guide (KEY)
1. Describe the shape of DNA. Double stranded helix
2. Copy and paste a picture of DNA that is 3 nucleotides long. Be sure to label which base pairs are
bonded together. Refer to online images for help
3. Explain why the DNA that you extracted in lab did not look like a double helix. (Hint: How much
of the DNA were you looking at in the test tube?) The actual DNA molecule is much too small to
be seen by the naked eye. Even with the most powerful microscopes, we can’t actually see it.
DNA REPLICATION
4. Where does DNA replication happen in a cell? nucleus
5. What is the end result of DNA replication? A second identical double stranded helix
6. Create a template strand of 5 codons. Next replicate them to make a new strand. Be sure to follow
the proper DNA-DNA “base pair rules”.
Template strand: AAA TTT GGG CCC ACT
New strand: TTT AAA CCC GGG TGA
DNA VS. RNA
7. Describe the differences and characteristics of DNA vs. RNA using the table below:
DNA
RNA
Deoxyribonucleic acid
Ribonucleic acid
Stands for?
Single (SS) or double
( D S ) stranded?
DS
SS
What type of sugar does it
contain?
Deoxyribose
Ribose
What are the 4 nitrogen
bases it contains?
ATCG
AUGC
Nucleus
Nucleus and cytoplasm
Where in the cell is it
found?
8. Identify the location(s) and function(s) of each of the three types of RNA
Nucleic Acid
mRNA
tRNA
rRNA
Location(s)
Nucleus, cytoplasm,
ribosome
Cytoplasm, ribosome
Cytoplasm
Function
Carries DNA message to cytoplasm
Carries amino acids to ribosome
Assembles ribosomes to a protein
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9. Transcribe and translate the following DNA codons into a protein (polypeptide). Use the decoder
wheel to do so.
DNA codons
mRNA codons
tRNA anticodons
Protein
AGG
UCC
AGG
SER
CCT
GGA
CCU
GLY
ATT
UAA
AUU
STOP
GTA
CAU
GUA
10. Define the following (Quizlet) terms:
a. Codon:
b. Anticodon:
c. Nucleotide:
d. Gene:
e. Genotype:
f. Phenotype:
g. Complementary:
h. Replication:
i. Transcription:
j. Translation:
11. Complete the table below outlining protein synthesis.
Where in the cell does it
occur?
Why does it happen?
Describe what happens
during this process.
Translation
Cytoplasm/Ribose
Transcription
Nucleus
DNA cannot physically meet up
with the ribosome in the
cytoplasm; it is too large a
polymer
The mRNA message (by itself)
doesn’t become the trait
(phenotype). The protein still must
be built.
Refer to Central Dogma steps.
Refer to Central Dogma steps.
SS mRNA
SS protein
What is the end product?
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12. Label all of the parts of the diagram below and describe what each of the parts are.
Word Wall: ribosome, mRNA, tRNA, amino acid, codon, anticodon
Nucleus
mRNA
Amino acid
Transfer RNA
(tRNA)
anticodon
Ribosome (rRNA)
codon
MUTATIONS
1. A change in a single gene is called a point mutation.
a. When a nucleotide is deleted a deletion mutation occurs.
b. When a nucleotide is added, a insertion mutation occurs.
c. When one nucleotide is changed for another, it is called a substitution mutation.
2. A strand of DNA contains the following bases: ATT CCG GGA TTT.
a. What are the amino acids are coded for?
STOP GLYCINE PROLINE LYSINE
b. If the ATT on the DNA strand is changed to ATG, what is the new amino acid sequence?
STOP becomes TYROSINE
c. If the CCG is mutated and becomes GCG, what is the new amino acid sequence?
GLYCINE becomes ARGININE
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